Architectures and protocols for multimedia wireless Internet access

by Xue, Qi

Abstract (Summary)

With the advances of broadband wireless data networks, it is predicted that by 2005 more than 1/3rd (750 million) of Internet users will have Internet connectivity through a wireless enabled device. To provide multimedia Internet access to the increasing number of wireless users, my dissertation proposes adaptive solutions across different protocol layers under diverse network architectures. At the medium access control (MAC) layer, we propose Spacing-based Channel Occupancy Regulation (SCORE) protocol that provides high bandwidth utilization, high communication efficiency, fair sharing, proportional service differentiation and heterogeneous users support with adjustable performance trade-offs via control theory guided parameter tuning. None of the earlier solutions in the literature provides such characteristics. In the meantime, some system issues like coverage extension and end-to-end quality assurance are better addressed at higher layer. To this end, we introduce a hybrid multihop wireless access networks (MWANs) architecture that extends the single hop wireless LANs architecture at both ends. To provide reliable multihop routing and end-to-end quality of service (QOS) support in MWANs, we propose two network layer protocols that provide IntServ and DiffServ solutions, respectively. While inheriting the desirable large geographical span of multihop wireless networks, MWANs also inherit some of the challenges such as poor and volatile performance due to multihop traffic contention. Between MAC and network layers, we present a novel solution that exploits the benefits of multiple orthogonal channels in MWANs and significantly improves network capacity and system performance. Designed for single transceiver device with no change to the existing MAC/network protocols and hardware, the proposed solution has a great potential to be deployed in existing systems that provide multiple non-interfering channels (e.g., IEEE 802.11 a/b/g). Independently located at different protocol layers, the above solutions can be applied either separately or in concert to improve the performance of multimedia wireless Internet access. Thorough theoretical analysis and extensive simulation studies are carried out to evaluate our proposed protocols. Compared to the state-of-the-art solutions, our solutions demonstrate significant advantages. Based on the results and the insights we have built, we propose some future research directions at the end of this dissertation.